This research focuses on the challenge of illuminating unknown aspects of the ecology and natural history of Monkeypox (MPX) viruses. The project links 3 disparate components- lab studies to characterize the course of infection and viremia in infected rodents, field studies of viral infections in natural rodent populations, and broad-scale spatial and temporal ecological-geographic analyses to provide a spatial, rangewide view of the system. The result will be a synthetic view of likely reservoir hosts of MPX viruses, and significant advances in the understanding of the natural transmission of the virus. The research team includes 3 academic institutions and US and foreign government agencies,and take advantage of novel technologies to explore MPX in both field and lab settings. This project complements other studies to date by basing laboratory challenge studies of potential reservoir host species on mammals obtained directly from MPX field sites, by incorporating intensive field surveys of African mammals for MPX infections, and by exploring novel Bayesian modeling approaches to understanding the distribution of MPX case-occurrences in animals and humans throughout Africa in both space and time. Data generated will characterize infection progression and pathogenesis of MPX in each mammal species using new in vivo imaging with recombinant (luciferase+) monkeypox constructs developed by our team; local prevalence of MPX infections in wildrodents at sites associated with recent human MPX cases; and spatiotemporal analyses that broaden the scope continentally, and that compare virus distributions with those of the mammal species that host them in a quantitative environmental context. The study will compare and contrast the infection characteristics of viruses from each of the two MPX clades (Western and Central African) in laboratory challenge studies, and will assess reservoir host potential of a set of mammal species by measuring length of viremia, tissue tropisms, and modes of viral shedding for various virus-rodent pairings.